A-Level Maths · Pure Mathematics
Differential Equations
What is it
A differential equation is an equation involving a rate of change (a derivative) — A-Level covers setting up and solving first-order separable differential equations, where variables can be separated onto each side.
Why it matters
Differential equations are how real-world change is modelled mathematically — population growth, cooling, radioactive decay — making this topic the bridge between abstract calculus and genuine scientific modelling.
Exam tip
After separating variables and integrating both sides, always use any given initial condition to find the constant of integration — leaving the constant unevaluated when a specific condition is given loses marks even if the method is otherwise correct.
Related topics
Want help mastering Differential Equations?
Tell us about the student's goals and confidence — we'll design a personalised plan.